JP5796229B2 - Power generator - Google Patents

Description

  The present invention relates to a power generation apparatus that converts vibration energy of a vibration member into electric energy by a power generation element.

  Conventionally, a vibration member (such as a vehicle or washing machine body) that supports a vibration source such as a power unit of a car or a motor of a washing machine is supported via a vibration isolator or a dynamic damper is attached. It has been devised to reduce.

  By the way, in order to respond to the recent high demands for energy saving, Japanese Patent Application Laid-Open No. 2011-152004 (Patent Document 1) proposes a power generation device that converts vibration energy into electric energy. That is, in the power generation device of Patent Document 1, a vibrating piezoelectric body is configured by attaching a piezoelectric element to a vibration system in which a mass member is elastically connected to a vibrating member by a spring member, and the piezoelectric element is formed by deformation of the spring member. The vibration energy is converted into electric energy.

  However, in the power generation device described in Patent Document 1, the vibration piezoelectric body is a one-degree-of-freedom vibration system in which a mass member is elastically supported by a spring member, and therefore, with respect to a vibration input having a frequency outside the natural frequency. As a result, sufficient deformation of the spring member may not occur, and power may not be obtained effectively.

  In Patent Document 1, it is also proposed to realize power generation with respect to vibration inputs in a wide frequency range by providing a plurality of vibrating piezoelectric bodies having different natural frequencies. However, even in a structure in which a plurality of vibrating piezoelectric bodies are provided in this way, the frequency range in which each vibrating piezoelectric body can generate power is limited, so that power generation is possible for vibration inputs in a wide frequency range. Was difficult.

JP 2011-152004 A

  The present invention has been made in the background of the above-described circumstances, and a solution to the problem is to provide a power generator having a novel structure capable of realizing highly efficient power generation with respect to vibration input in a wide frequency range. There is.

That is, the first aspect of the present invention includes a vibration system attached to the vibration member, and the power generation element attached to the vibration system converts the vibration energy of the vibration member into electrical energy. The vibration system includes a first vibration system in which a first mass member is elastically supported by a first spring member, and a second mass member elastically connected to the first mass member by a second spring member. A multi-degree-of-freedom vibration system including the second vibration system, and the power generation element is disposed between the first mass member and the second mass member, The vibration exerted on the first mass member from the vibration member is transmitted to the second mass member, and the first mass member and the second mass member are relatively displaced, whereby the vibration energy of the vibration member is increased. It will be input to the power generation element And the natural frequency of the first vibration system is different from the natural frequency of the second vibration system, while the first spring member is formed of a rubber elastic body, A rubber elastic body is provided between the opposing surfaces in the direction substantially orthogonal to the vibration input direction of the first mass member and the attachment member attached to the vibration member, and at a plurality of locations on the circumference of the first mass member. Furthermore, the first mass member has a hollow structure having a void therein, the second vibration system is accommodated in the void, and the second mass system is accommodated. The second spring member in the vibration system is formed of a leaf spring, and the power generation element is attached to the leaf spring, and the second mass member is attached to one end side of the leaf spring, The other end side of the leaf spring is in the space in the first mass member. That are brought support located inwardly of said cavity than the peripheral wall of the first mass member by being attached to a support portion which projects, and features.

  According to the power generation device having the structure according to the first aspect, the relative displacement amount of the first mass member and the second mass member is largely ensured by the resonance phenomenon at a plurality of different natural frequencies. The power generation amount of the power generation element obtained according to the relative displacement amount between the first mass member and the second mass member can be efficiently obtained.

  In addition, when a power generation element is arranged between the first and second mass members of the multi-degree-of-freedom vibration system, when the vibration is input in a frequency range in which the first mass member and the second mass member are relatively displaced in opposite phases. Even when the input vibration has a frequency outside the natural frequency of the vibration system, a large amount of relative displacement between the first mass member and the second mass member is ensured. Therefore, the power generation amount of the power generation element can be sufficiently obtained with respect to vibration input in a wide frequency range, and electric power can be effectively obtained.

  Here, the relative displacement means that the vibration of the vibration member is exerted on the first mass member via the first spring member, the first mass member itself vibrates, and further, the vibration is the second spring member. It is transmitted to the second mass member via, and the second mass member is displaced with respect to the first mass member.

Thus, according to the power generation device according to this aspect, not only for a vibration input having a frequency that matches the mechanical natural frequency of the vibration system, but also for a vibration input in a frequency region that deviates from the natural frequency, Effective power generation is realized, and vibration energy can be efficiently converted into electric energy.
In the power generation device according to the first aspect of the present invention, an aspect in which the first spring member is formed of a rubber elastic body is employed.
According to the first aspect, since the first spring member is formed of a rubber elastic body having a damping performance, the first mass member and the second mass member with respect to vibration input in a wider frequency range. The relative displacement is ensured, and effective power generation is realized .
According to a second aspect of the present invention, in the power generation device described in the first aspect, the first mass member and the second mass member are in a vibration frequency range to be generated by the vibration member. They are set so as to be displaced in mutually opposite phases.

According to a third aspect of the present invention, in the power generation device described in the first or second aspect, the natural frequency of the second vibration system is lower than the natural frequency of the first vibration system. The frequency is set.

In the power generator of the third aspect, since the natural frequency of the second vibration system is set to a lower frequency than the natural frequency of the first vibration system, the spring constant of the second spring member is set to It is easy to ensure the relative displacement amount of the second mass member with respect to the first mass member by setting it small, and the power generation efficiency corresponding to the relative displacement amount of the first mass member and the second mass member is further improved. It is easy to plan. Further, in the region having a frequency lower than the anti-resonance frequency in the two-degree-of-freedom vibration system, the first mass member and the second mass member are displaced in the same phase with respect to the input vibration. Energy is efficiently applied to the first and second vibration systems, and effective power generation can be realized.

According to a fourth aspect of the present invention, in the power generation device described in any one of the first to third aspects, the natural frequency of the first vibration system is the electrical frequency of the second vibration system. The frequency is set higher than the antiresonance frequency.

According to the fourth aspect, the resonance at the secondary natural frequency of the vibration system in a region of a frequency higher than the electrical anti-resonance frequency in which a decrease in power generation efficiency is likely to be a problem in the power generator of the vibration system with one degree of freedom. The power generation efficiency is improved based on the above, and effective power generation with respect to vibration input in a wider frequency range can be realized.

According to a fifth aspect of the present invention, in the power generation device described in any one of the first to fourth aspects, the natural frequency of the first vibration system is equal to the natural frequency of the second vibration system. √2 times or less.

According to the fifth aspect, the first vibration system and the second vibration are obtained by transmitting the vibrations of the first vibration system and the vibration of the second vibration system to each other to form a coupled vibration state. The vibration state of the system can be maintained in a complementary manner over a wide frequency range, and efficient power generation can be realized.

According to a sixth aspect of the present invention, in the power generation device described in any one of the first to fifth aspects, the resonance response magnification of the second vibration system is greater than the resonance response magnification of the first vibration system. And the product of the mass of the first mass member and the resonance response magnification of the first vibration system is equal to the mass of the second mass member and the resonance response magnification of the second vibration system. It is larger than the product.

According to the sixth aspect, since the resonance response magnification of the second vibration system is made larger than the resonance response magnification of the first vibration system, the amplitude of the second mass member is ensured to be large at the time of vibration input. Efficient power generation is realized in the power generation element disposed in the second vibration system. Further, the canceling damping action acting between the first vibration system and the second vibration system is suppressed, and the vibration states of the first vibration system and the second vibration system are stably secured. As a result, power generation effective for broadband vibration is realized.

According to a seventh aspect of the present invention, in the power generation device described in any one of the first to sixth aspects, a stopper unit that limits a relative displacement amount of the second mass member with respect to the first mass member. Is provided.

According to the seventh aspect, since excessive relative displacement between the first mass member and the second mass member is prevented by the stopper means, the input to the power generation element is limited, and damage to the power generation element is prevented. Is done.

One aspect of the present invention is the power generation apparatus according to any one of the first to seventh aspects, wherein the first spring member is formed of a rubber elastic body and the second spring member. Is formed by a leaf spring, and one end side of the leaf spring is attached to the first mass member, and the second mass member is attached to the other end side of the leaf spring. While vibration is applied to the leaf spring, the power generating element is attached to the leaf spring.

According to such an aspect, the frequency characteristic can be broadened effectively by the high damping capacity of the rubber elastic body constituting the first vibration system, and the leaf spring constituting the second vibration system can be reduced. A large vibration magnification can be obtained by the damping capacity. Therefore, in the leaf spring which is the second spring member, a large elastic deformation is induced with respect to the input vibration in a wide frequency range, and the power generation element mounted on the leaf spring further stabilizes the power generation efficiency. Can be demonstrated. As the power generation element mounted on the leaf spring, a piezoelectric element, a magnetostrictive element, or the like that can convert energy of mechanical physical quantities such as strain, deformation, and stress of the leaf spring is preferably employed. In addition, a metal spring such as spring steel is preferably used as the leaf spring, but a resin spring or the like can also be used depending on conditions, and the surface is covered with rubber to supplement the desired damping capacity. Is also possible.

An eighth aspect of the present invention is the power generation device according to any one of the first to seventh aspects, wherein the vibration member has a plurality of types of vibrations having maximum vibration levels in different frequency ranges. Is attached to a part exerted on the vibration system.

According to the eighth aspect, by applying the power generation device having the structure according to the present invention using the multi-degree-of-freedom vibration system to a specific vibration member having vibration peaks in a plurality of frequency ranges, the power generation device is stable in various situations. It becomes possible to obtain power generation efficiency. Note that examples of the vibration member to which the present embodiment is applied include an electric washing machine having a different vibration frequency according to the laundry weight and the like, and an automobile having a different vibration frequency according to the running condition.

According to a ninth aspect of the present invention, in the power generation device described in any one of the first to eighth aspects, the mass of the first mass member is 10% of the equivalent mass of the vibration member. This is what has been described above.

According to the ninth aspect, it is possible to obtain an effective vibration damping effect by causing the first vibration system to function as a dynamic damper that cancels and reduces the vibration of the vibration member.
According to a tenth aspect of the present invention, in the power generation device described in any one of the first to ninth aspects, the first mass member has a hollow structure including an accommodation space therein, The second vibration system is accommodated in the accommodation space.
According to the tenth aspect, since the gravity center positions of the first mass member and the second mass member are low and set close to each other, directions other than the intended directions of the first and second mass members The vibration can be suppressed to be small, and the vibration in the target direction can be stably input, and the power generation efficiency can be improved by the first and second vibration systems. In addition, since the second vibration system is housed and disposed in the housing space separated from the external space, it is not necessary to separately provide a dustproof or waterproof member for the second vibration system.

  According to the present invention, the power generation element is disposed between the first mass member and the second mass member constituting the multi-degree-of-freedom vibration system, and the relative relationship between the first mass member and the second mass member is determined. Electric power can be obtained in the power generation element according to the amount of displacement. Therefore, power can be obtained by the power generating element with respect to vibration inputs having a plurality of different frequencies, and vibration signals in a wide frequency range in which the first mass member and the second mass member are displaced in opposite phases. Thus, efficient power generation by the power generation element is realized.

BRIEF DESCRIPTION OF THE DRAWINGS The longitudinal cross-sectional view which shows the electric power generating apparatus as one Embodiment of this invention. The vibration model for demonstrating the electric power generating apparatus shown by FIG. The graph which shows the measurement value of the electric power generation amount in the electric power generating apparatus shown by FIG. 1 together with the comparative example data comprised by the 1 degree-of-freedom vibration system as Example data. The graph which shows the correlation of the frequency and amplitude in the case of handling each vibration system which comprises the electric power generating apparatus shown by FIG. 1 as a 1 degree-of-freedom vibration system. Schematic which shows the electrical equivalent circuit of the 2nd vibration system in the electric power generating apparatus shown by FIG. The graph which shows the correlation with the frequency of an input vibration in the equivalent circuit shown by FIG. 5, impedance, and a phase. The longitudinal cross-sectional view which shows the electric power generating apparatus as another embodiment of this invention. The longitudinal cross-sectional view which shows the electric power generating apparatus as another embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows a power generation device 10 as one embodiment of the present invention. As shown in the vibration model of FIG. 2, the power generation apparatus 10 is attached to the body 12 via the first vibration system 14 attached to the body 12 as a vibration member and the first vibration system 14. A multi-degree-of-freedom vibration system including the second vibration system 16 is provided. In the following description, unless otherwise specified, the vertical direction refers to the vertical direction in FIG. 1 that is the main vibration input direction of the vibration member 12.

  More specifically, the first vibration system 14 has a structure in which the mounting member 18 and the first mass member 20 are elastically connected by a connecting rubber elastic body 22 as a first spring member. By fixing 18 to the body 12 with a bolt or the like, the first mass member 20 is elastically connected to the body 12 by a connecting rubber elastic body 22. The shape and forming material of the first mass member 20 are not particularly limited. However, it is desirable that the first mass member 20 be formed of a material having a large specific gravity for the purpose of downsizing. This is a member having a rectangular block shape. Further, the first mass member 20 is integrally formed with a support protrusion 24 protruding upward, and a screw hole is formed so as to open on the upper surface thereof. The connecting rubber elastic body 22 is a rectangular block-shaped rubber elastic body, and is interposed between the mounting member 18 and the first mass member 20 that are vertically opposed to each other, and the lower surface is fixed to the mounting member 18. In addition, the upper surface is fixed to the first mass member 20.

  In addition, as a material of the rubber elastic body employed as the connecting rubber elastic body 22, natural rubber, synthetic rubber, or a blend rubber of natural rubber and synthetic rubber is used. Synthetic rubbers include styrene-butadiene rubber, butadiene rubber, isoprene rubber, chloroprene rubber, isobutylene-isoprene rubber, chlorinated-isobutylene-isoprene rubber, acrylonitrile-butadiene rubber, hydrogenated-acrylonitrile-butadiene rubber, ethylene-propylene-diene rubber. , Ethylene-propylene rubber, acrylic rubber, silicone rubber and the like.

  In addition, the first mass member 20 of the present embodiment includes a cover member 28. The cover member 28 has a rectangular bowl shape that opens downward, and a flange-shaped fixing piece provided in the opening is fixed to the first mass member 20 with a bolt or the like, whereby the first mass member 20 is attached so as to cover the upper surface. By mounting the cover member 28 as described above, an accommodation area 30 separated from the outside by the cover member 28 is defined above the first mass member 20, and the support protrusion of the first mass member 20 is formed. 24 protrudes into the accommodation area 30.

Furthermore, the mass: m ₁ of the first mass member 20 including the cover member 28 is 10% or more (m ₁ ≧ 0.1 * M) with respect to the equivalent mass: M of the body 12. Is desirable. As a result, the first mass member 20 has a sufficient influence on the vibration state of the body 12 and can function as a dynamic damper. Therefore, it is expected that the vibration of the body 12 is reduced by canceling out the vibration.

  In addition, the second vibration system 16 is disposed in the accommodation region 30. In the second vibration system 16, the second mass member 32 is fixed to one end of a leaf spring 34 as a second spring member, and the other end of the leaf spring 34 is a first mass member. By being fixed to 20, the second mass member 32 has a cantilever-like structure in which the second mass member 32 is elastically connected to the first mass member 20 by a leaf spring 34.

The second mass member 32 has a rectangular block shape, and is formed of a material having a high specific gravity such as iron, like the first mass member 20. In the present embodiment, the mass of the second mass member 32: m ₂ is set so as to satisfy m ₁ * X> m ₂ * Q with the mass of the first mass member 20: m _1. Is done. X represents the response magnification (resonance response magnification) at the natural frequency of the first vibration system 14, and Q represents the resonance response magnification of the second vibration system 16. In this embodiment, The resonance response magnification Q of the second vibration system 16 is larger than the resonance response magnification X of the first vibration system 14 (X <Q). Also, preferably, the second mass member 32 Mass: m ₂ is the mass of the first mass member 20: is 1/5 times or less with respect to _{m 1 (m 2 ≦ m 1} /5) Thus, the second mass member 32 is smaller and lighter than the first mass member 20. Since the second mass member 32 is lighter than the first mass member 20 as described above, the leaf spring 34 is set while setting the natural frequency of the vibration system in accordance with the frequency of the power generation target vibration. Therefore, the relative displacement of the first mass member 20 with respect to the second mass member 32 can be effectively generated.

  The leaf spring 34 is a longitudinal plate-like metal member formed of conductive spring steel, and the second mass member 32 is fixed to one end portion in the longitudinal direction and the other end portion in the longitudinal direction. Is superposed on the support protrusion 24 of the first mass member 20 and screwed. Accordingly, the second mass member 32 is elastically connected to the first mass member 20 via the leaf spring 34, and the relative displacement of the second mass member 32 with respect to the first mass member 20 is the leaf spring. 34 is allowed by elastic deformation in the shear direction which is the plate thickness direction (vertical direction in FIG. 1). As is clear from this, the power generation apparatus 10 includes a two-degree-of-freedom vibration system including a first vibration system 14 and a second vibration system 16.

In this embodiment, the mechanical natural frequency: _fr2 when the second vibration system 16 is handled as a one-degree-of-freedom vibration system is the mechanical frequency when the first vibration system 14 is handled as a one-degree-of-freedom vibration system. Natural frequency: set to a frequency lower than f _r1 (f _r2 <f _r1 ). Furthermore, the natural frequency of the first vibration system 14 alone: _fr1 is less than or equal to √2 times the natural frequency of the second vibration system 16 alone: _fr2 ( _fr2 < _fr1 ≤ √2 * _fr2 ) It is desirable that Thereby, the relative displacement of the first mass member 20 with respect to the second mass member 32 is suppressed by the vibration suppression action by the so-called sky hook damper effect. It is possible to avoid problems such as deterioration. Note that the mechanical natural frequency f _r1 in the one-degree-of-freedom vibration system of the first vibration system 14 alone is the mass of the first mass member 20: m ₁ and the spring constant of the coupling rubber elastic body 22: k _1. From [Equation 1]. The mechanical natural frequency f _r2 in the one-degree-of-freedom vibration system of the second vibration system 16 alone is calculated from the mass of the second mass member 32: m ₂ and the spring constant of the leaf spring 34: k ₂ [Equation 2 ] Is calculated as follows.

  A power generation element 38 is fixed to the leaf spring 34. As the power generation element 38, a general piezoelectric element, an electrostrictive element, or the like is suitably used, and the first mass member 20 and the second mass member 32 are superposed on and fixed to the surface of the leaf spring 34. Between the two. When the vibration is input, the external force exerted on the first mass member 20 from the body 12 is transmitted to the second mass member 32, so that the first mass member 20 and the second mass member 32 are relative to each other. When the leaf spring 34 is displaced and elastically deformed, the power generating element 38 is deformed together with the leaf spring 34 to generate electricity. In other words, vibration energy is input to the power generation element 38 by the relative displacement between the first mass member 20 and the second mass member 32, and the power generation element 38 is connected to the first mass member 20 and the first mass member 20. The vibration energy is converted into electric energy according to the relative displacement amount of the second mass member 32. An electric circuit 40 is connected to the power generation element 38 and is electrically connected to a power use device (device 42) such as a rectifier circuit, a power storage device, and a sensor. In the case where a piezoelectric element is employed as the power generation element 38, for example, a ceramic material or a single crystal material is employed as the forming material. More specifically, for example, any one of lead zirconate titanate, aluminum nitride, lithium tantalate, lithium niobate, and the like can be suitably used as the piezoelectric element forming material.

  In the present embodiment, the power generating element 38 fixed to the leaf spring 34 is disposed in the accommodation region 30 separated from the external space by the cover member 28 and covered with the cover member 28, thereby Adherence of foreign matters such as dust and dust is prevented.

  In the present embodiment, stopper means 44 for limiting the relative displacement amount of the second mass member 32 with respect to the first mass member 20 is provided, and excessive deformation of the leaf spring 34 and the power generating element 38 is prevented. Damage to the power generating element 38 is avoided. Specifically, the displacement of the second mass member 32 is limited by the second mass member 32 coming into contact with the upper surface of the first mass member 20 and the inner surface of the upper bottom wall of the cover member 28. The stopper means 44 includes the first mass member 20 and the cover member 28. Further, in the present embodiment, the stopper rubber 46 is fixed to the upper surface of the first mass member 20 and the inner surface of the upper bottom wall of the cover member 28, and the second mass member 32 is the first mass member 20. Further, the cover member 28 is brought into contact with the cover member 28 through a stopper rubber 46 in a shock-absorbing manner.

  The power generation apparatus 10 according to the present embodiment having such a structure is configured to convert vibration energy of the body 12 into electric energy by the power generation element 38 and take it out when the body 12 is attached to the body 12. Therefore, in the power generation device 10, a two-degree-of-freedom vibration system is provided, and the power generation element 38 is disposed between the first and second mass members 20 and 32, so that the power generation element 38 can efficiently generate power. It has come to be realized.

Such a power generation device 10 mechanically includes a first vibration system 14 including a first mass member 20 and a connecting rubber elastic body 22 as a first spring member, as described above, and a second mass. Since the two-degree-of-freedom vibration system in which the member 32 and the plate spring 34 as the second spring member are connected in series constitutes a two-degree-of-freedom vibration system, a known multi-degree-of-freedom vibration It is possible to analyze using a model. That is, the vibration model of the mechanical vibration system of the power generation apparatus 10 is as shown in FIG. 2 and is expressed by a known two-degree-of-freedom motion equation shown in [Equation 3]. In [Equation 3], x ₁ corresponds to the displacement amount of the first mass member 20 in the power generation device 10, and x ₂ corresponds to the displacement amount of the second mass member 32 in the power generation device 10. Further, F ₀ sin2πft in [Equation 3] corresponds to the vibration load input from the body 12 in the power generation apparatus 10.

As is well known, Ω ₁ and Ω ₂ (Ω ₁ <Ω ₂ ) obtained as the solution of the motion equation of the general two-degree-of-freedom vibration system shown in [Equation 3] are 2 freedoms respectively. This is the natural frequency of the degree vibration system. Incidentally, the power generation device 10 as a mechanical device is grasped as a two-degree-of-freedom vibration system, but the vibration energy to the power generation element 38 is exerted as a relative displacement amount of the second mass member 32 with respect to the first mass member 20. It is. Therefore, when the phase difference between the first mass member 20 and the second mass member 32 is approximately 180 degrees and is displaced in the opposite direction, the vibration energy exerted on the power generation device 10 is efficiently applied to the power generation element 38. A large amount of generated power can be obtained.

More specifically, the natural frequency of the above-described two-degree-of-freedom vibration system: Ω ₁ and Ω ₂ both theoretically have a peak mass displacement momentum, but the first natural frequency: Ω ₁ Since the first and second mass members 20 and 32 move in the same phase at low frequencies up to, it is difficult to efficiently convert the input vibration energy into generated power. On the other hand, at frequencies from the _first natural frequency: Ω ₁ to the second natural frequency: Ω ₂ , the first and second mass members 20 and 32 move in opposite phases. Can be efficiently converted to generated power to obtain large generated power.

Here, in order to facilitate understanding, the second vibration system 16 can be regarded as a one-degree-of-freedom system in which the second mass member 32 is elastically displaced relative to the first mass member 20. Then, the second mass member 32 of the second vibration system 16 has the first vibration system 14 at the mechanical natural frequency f _r2 as the one-degree-of-freedom vibration system of the second vibration system 16. The phase with respect to the first mass member 20 is reversed. In addition, in the frequency range of the natural frequency f _r2 , the relative displacement amount of the second mass member 32 relative to the first mass member 20 is also efficiently obtained due to the mechanical resonance phenomenon of the second vibration system 16. It becomes possible.

From this, in the present embodiment in which the mechanical vibration frequency is set to a low frequency region in the second vibration system 16 than in the first vibration system 14, the vibration mode of the two-degree-of-freedom vibration system is used. The first and second mass members 20, 32 move in the opposite phase on the high frequency side natural frequency: even in the low frequency range up to Ω ₂ , the mechanical characteristic of the second vibration system 16 as a one-degree-of-freedom vibration system In the frequency range exceeding the frequency: f _r2 , the phase of the second mass member 32 with respect to the first mass member 20 is inverted, so that large generated power can be obtained with excellent power generation efficiency.

  This is also confirmed by the results of actual measurement of the generated power by the inventor. That is, the frequency characteristic of the power generated by the power generation element 38 was measured by making a prototype of the power generation apparatus 10 having the structure according to the present embodiment shown in FIGS. 1 and 2 and performing sweep excitation from the body 12 side. . The result is shown in FIG. In FIG. 3, the actual measurement value of the generated power of the power generation element 38 is indicated by a solid line as the example data, and one mechanical freedom corresponding to the second vibration system alone in which the first vibration system is omitted. The actual measurement value of the power generated by the power generation device composed of the power system structure is indicated by a broken line as comparative example data.

As is clear from FIG. 3, in the comparative example consisting essentially of the second vibration system alone, the generated power is only one in the frequency range of the mechanical natural frequency: _fr2 of the second vibration system. If it has only a peak and the input vibration deviates from the natural frequency f _r2 , the power generation efficiency is significantly reduced. On the other hand, in the embodiment of the present invention, the generated power has peaks at two frequencies: P ₁ and P ₂ , respectively, and the frequency range between these two frequencies: P ₁ and P ₂ high power generation efficiency over a wide frequency range leading to a high frequency region exceeding the P ₂ is maintained. Here, the peak frequency on the high-frequency side: P ₂ is the natural frequency on the high-frequency side: Ω ₂ where the first and second mass members 20 and 32 move in opposite phases in the vibration mode of the two-degree-of-freedom vibration system. Corresponding frequency. On the other hand, the peak frequency on the low frequency side: P ₁ is the natural frequency on the low frequency side: Ω ₁ where the first and second mass members 20 and 32 move in opposite phases in the vibration mode of the two-degree-of-freedom vibration system. Further, the second vibration system 16 is a frequency substantially corresponding to the natural frequency f _r2 at which the phase with respect to the first mass member is inverted as a one-degree-of-freedom vibration system.

In the present embodiment, the resonance response magnification Q of the second vibration system 16 is larger than the resonance response magnification X of the first vibration system 14 (X <Q), and the first mass The product of the mass of the member 20: m ₁ and the resonance response magnification: X of the first vibration system 14 is the mass of the second mass member 32: m ₂ and the resonance response magnification of the second vibration system 16: Q (M ₁ * X> m ₂ * Q). Thereby, at the time of vibration input, the amplitude of the second mass member 32 and the elastic deformation amount of the leaf spring 34 are ensured to be large, and the power generation by the power generation element 38 is efficiently realized. Further, since the excitation force exerted on the first mass member 20 in the resonance state is made larger than the excitation force exerted on the second mass member 32 in the resonance state, the second vibration system 16 The destructive damping action of the input vibration due to is suppressed, and the relative displacement between the first mass member 20 and the second mass member 32 is stably generated, so that more effective power generation is realized over a wide band. The

Further, in the power generation apparatus 10, the mass: m _{2 of} the second mass member 32 is 1/5 times or less than the mass: m ₁ of the first mass member 20, and the two-degree-of-freedom vibration system While the mechanical natural frequency is set to a predetermined value, the spring constant k ₂ of the leaf spring 34 is set small. Therefore, relative displacement of the second mass member 32 with respect to the first mass member 20 is likely to occur, and the amount of power generated by the power generation element 38 can be obtained efficiently.

In the present embodiment, the mechanical natural frequency f _r2 in the single-degree-of-freedom vibration system of the second vibration system 16 alone is the mechanical natural frequency in the single-degree-of-freedom vibration system of the single first vibration system 14. Frequency: set to a frequency lower than f _r1 (f _r2 <f _r1 ). Thereby, the relative displacement of the second mass member 32 with respect to the first mass member 20 is sufficiently generated at the time of vibration input, and corresponds to the relative displacement amount of the first mass member 20 and the second mass member 32. The power generation efficiency can be improved.

Furthermore, since f _r2 <f _r1 , the mechanical natural frequency in the one-degree-of-freedom vibration system of the second vibration system 16: f _r2 to the one-degree-of-freedom vibration system of the first vibration system 14 In the frequency range up to the mechanical natural frequency: _fr1 , the first mass member 20 is displaced in phase with the input vibration. Therefore, the vibration energy is more efficiently transmitted to the second vibration system 16 via the first mass member 20 that vibrates and displaces in phase with respect to the body 12, thereby further improving the power generation efficiency. Can be. On the other hand, when f _r2 >> f _r1 , the first vibration system 14 is displaced in the opposite phase to the input vibration at the low frequency side natural frequency: Ω ₁ in the two-degree-of-freedom vibration system. The vibration energy cannot be efficiently transmitted to the second vibration system 16. Therefore, by setting f _r2 <f _r1 as in the present embodiment, the frequency range between P _{1 and} P ₂ shown in FIG. 3 is set sufficiently large, and excellent power generation efficiency is obtained in a wider frequency range. It becomes possible.

  In addition, the spring component of the first vibration system 14 constituting the two-degree-of-freedom vibration system of the power generation apparatus 10 is composed of a connected rubber elastic body 22 formed of a rubber elastic body, while the second vibration system 16 is. The spring component is composed of a leaf spring 34 made of metal. As a result, as shown in FIG. 4, the second vibration system 16 can obtain a power generating amplitude with a large resonance response magnification only in a narrow frequency region near the resonance frequency, while the first vibration system. 14, an amplitude capable of generating power can be obtained over a wide frequency range with a resonance response magnification smaller than that of the second vibration system 16. Therefore, by adopting the first vibration system 14 and the second vibration system 16 in combination, the first vibration system 14 can generate power that can be realized only in a remarkably narrow frequency range with the second vibration system 16 alone. By broadening the characteristics based on the damping performance of the connected rubber elastic body 22, it is effectively realized for vibration input in a wider frequency range. Thereby, effective power generation is possible under various vibration input conditions, and the power generation apparatus 10 having high practicality can be provided. In FIG. 4, the frequency-amplitude characteristic in the single-degree-of-freedom vibration system of the first vibration system 14 alone is shown by a solid line, and the frequency-amplitude in the single-degree-of-freedom vibration system of the second vibration system 16 alone. The characteristic is indicated by a broken line.

In the power generation apparatus 10, the mechanical natural frequency f _r1 in the single-degree-of-freedom vibration system of the first vibration system 14 alone is a multi-degree-of-freedom configured by the first and second vibration systems 14 and 16. By setting the electrical anti-resonance frequency of the vibration system to a frequency higher than f _a2 (f _r1 > f _a2 ), power generation with respect to a vibration input in a wide frequency range is realized. Hereinafter, description will be made using an equivalent circuit in consideration of the electrical characteristics of the second vibration system 16 shown in FIG.

The equivalent circuit of FIG. 5 is a circuit showing the mechanical-electrical conversion characteristic which is the piezoelectric characteristic of the second vibration system 16 in which the power generation element 38 (piezoelectric element) is disposed, and is equivalent series arranged in series. Inductance: L ₁ and equivalent series capacitance: C ₁ and equivalent series resistance: R _1, and parallel capacitance: C ₀ arranged in parallel to these L ₁ , C ₁ , R ₁ , generate electricity The mechanical vibration of the element 38 is expressed as an electric circuit.

L ₁ , C ₁ , and R ₁ are constants that are uniquely determined according to the vibration mode. On the other hand, C ₀ is an electrostatic capacity generated by the power generation element 38 functioning as a dielectric, and is a constant defined by the size, dielectric constant, and the like of the power generation element 38.

Since the equivalent circuit in consideration of the electrical characteristics of the second vibration system 16 is composed of such L ₁ , C ₁ , R ₁ , and C ₀ , the impedance of the second vibration system 16 is the input With respect to the frequency of vibration, the graph is as shown in FIG. 6, and the local resonance value is a minimum value at a series resonance frequency: f _r2 and the maximum value is an electrical anti-resonance frequency (parallel resonance frequency): f _a2. Become. The series resonance frequency is substantially the same as the mechanical resonance frequency f _{r2 of} the second vibration system 16. Strictly speaking, the series resonance frequency f _r2 is slightly different from the frequency at which the impedance of the second vibration system 16 becomes a minimum value due to the influence of C ₀ , but is regarded as substantially the same here. Similarly, the parallel resonance frequency: f _a2 is slightly different from the frequency at which the impedance of the second vibration system 16 becomes a maximum value, but is considered to be substantially the same here.

As apparent from the graph of FIG. 6, the second vibration system 16 provided with the power generation element 38 can generate a large amount of power generation at the series resonance frequency: f _r2 , while generating power at the parallel resonance frequency: f _a2 . The amount of power decreases, and the power generation amount remains relatively small even in a frequency range higher than f _a2 .

In the equivalent circuit of the second vibration system 16, the series resonance frequency: _fr2 and the parallel resonance frequency (antiresonance frequency): _fa2 are defined by the following [Equation 4] and [Equation 5].

On the other hand, in this embodiment, since the vibration system of the power generation apparatus 10 has two degrees of freedom, the mechanical secondary natural frequency: Ω ₁ of the vibration system of the power generation apparatus 10 is set to the mechanical anti-resonance of the vibration system. By setting the frequency higher than the frequency, a decrease in the amount of power generation can be suppressed over a wide frequency range. Therefore, in general, the mechanical natural frequency: f _r1 of the first vibration system 14 is set to a frequency higher than the parallel resonance frequency: f _a2 of the equivalent circuit, thereby reducing the generation efficiency over a wide band. Can be prevented.

More preferably, the mechanical resonance frequency: f _{r1 of} the first vibration system 14 alone is less than or equal to √2 times the mechanical resonance frequency: f _r2 of the second vibration system 16 alone (f _r1 By setting ≦ √2 * _fr 2), a large relative displacement amount between the first mass member 20 and the second mass member 32 can be secured for vibration input in a wide frequency range. Therefore, highly efficient power generation by the power generation element 38 is realized for vibration input in a wide frequency range. In short, the mechanical resonance frequency f _r1 of the first vibration system 14 alone is preferably set in the range of f _a2 <f _r1 ≦ √2 * f _r2 .

In addition, when the present inventor examined by experiment etc., it was made to transmit mutually the vibration in the 1st vibration system 14, and the vibration in the 2nd vibration system 16 by setting it as _fr1 <= √2 * _fr2. Thus, a coupled vibration state can be obtained. That is, for example, when the frequency of the input vibration changes, even if the first vibration system 14 and the second vibration system 16 vibrate completely independently of each other, By virtue of the influence of the other vibration system on this vibration system, a certain vibration state can be maintained. As a result, both vibrations are exerted and the vibration states in both vibration systems 14 and 16 can be maintained in a complementary manner. And its maintenance can be achieved more efficiently. In the first and second vibration systems 14 and 16, each resonance frequency is set so as to satisfy f _r1 ≦ √2 * f _r2 , so that the vibration state can be complementarily maintained by coupling of vibrations. The realization can be understood with the aid of, for example, Japanese Patent No. 4862286.

  Next, FIGS. 7 and 8 show power generation apparatuses 50 and 52 as another embodiment of the present invention, respectively. Note that in these power generation devices 50 and 52, members and parts having the same structure as in the above embodiment are given the same reference numerals as those in the above embodiment, and detailed descriptions thereof are given. Omitted.

  That is, in the power generation apparatus 50 shown in FIG. 7, the first mass member 54 has a hollow structure, and the first mass member 54 is provided with an accommodation space 56 that is substantially blocked from the external space. It has been. The first mass member 54 having such a hollow structure is formed by, for example, overlapping a substantially flat cylindrical upper mass 64 on a substantially bottomed cylindrical lower mass 62 provided with a bottom wall 58 and a peripheral wall 60 to form a lower portion. This is realized by fixing the upper opening of the mass 62 so as to cover it.

  And the 2nd vibration system 16 made into the structure substantially the same as the said embodiment in the state accommodated in the accommodation space 56 of this 1st mass member 54 is provided. The accommodation space 56 is large enough to allow displacement of the second mass member 32 due to elastic deformation of the leaf spring 34 as the second spring member. Further, in the accommodation space 56, stopper rubbers 46 are respectively provided on both side walls in the displacement direction of the second mass member 32, and the displacement amount of the second mass member 32 is limited in a buffering manner. It is like that.

  In the power generation device 50 having such a structure, the position of the center of gravity of the first mass member 54 in the first vibration system 14 and the position of the center of gravity of the second mass member 32 in the second vibration system 16 are increased. It becomes possible to set in close proximity in the vertical direction. In addition, the first mass member 54 and the second mass member 32 have a height from the support surface which is a fixed surface to the body 12 of the connecting rubber elastic body 22 as the first spring member serving as the vibration input reference surface. Positioning can be performed with a reduced height.

  Therefore, the vibration of the first mass member 54 and the second mass member 32 at the time of vibration input is suppressed, and the vibration displacement in the vertical direction that is the target main vibration input direction is generated more stably. As a result, the elastic deformation amount of the connecting rubber elastic body 22 and the leaf spring 34 is increased, and the conversion efficiency of vibration energy into electric energy can be further improved.

  In addition, since the region where the second vibration system 16 is disposed is blocked from the external space by the first mass member 54, the second vibration system 16 is arranged without requiring a separate cover structure or the like. It is also possible to provide dustproof performance and waterproof performance with a simple structure in the installation area.

  In addition, since the first mass member 54 has a hollow structure, the second vibration system 16 is accommodated in the accommodation space 56 while ensuring a large mass weight in the outer peripheral portion having a large volume, and the above-described embodiment. Thus, a large upward projection from the first mass member 54 can be avoided. As a result, it is possible to keep the size of the entire vibration isolator in particular in the height direction small while securing the mass of the first mass member 54 sufficiently.

  Further, the power generation device 52 shown in FIG. 8 is housed in the accommodation space 56 of the first mass member 54 having a hollow structure in the same manner as the power generation device 50 shown in FIG. Two vibration systems 16 are provided. On the other hand, the first mass member 54 is elastically connected to the body 12 serving as the vibration member by a first spring member 66 provided on the outer peripheral surface of the peripheral wall 60.

  That is, the mounting member 68 fixed to the body 12 with a bolt or the like is formed with a vertical wall structure spaced apart on the outer peripheral side of the first mass member 54, and the outer peripheral surface of the first mass member 54 is The mounting member 68 is opposed to the mounting member 68 in a direction substantially orthogonal to the main vibration input direction. The first mass member 54 is attached to the mounting member by disposing the first spring member 66 made of a rubber elastic body between the outer peripheral surface of the first mass member 54 and the mounting surface of the mounting member 68. 68 is elastically supported.

  The first spring member 66 may be provided over the entire circumference of the first mass member 54, but may be provided at an appropriate number of locations on the circumference.

  In the power generation device 52 having such a structure, the first spring member 66 in the first vibration system 14 is mainly sheared and deformed in the main vibration input direction by the vibration from the body 12, so that the low dynamic spring tuning is performed. Thus, the degree of freedom of characteristic tuning can be improved. In the power generation device 52 of the present embodiment, the characteristic tuning may be performed by additionally inserting a compression rubber between the opposing surfaces of the bottom wall 58 of the first mass member 54 and the bottom wall of the mounting member 68. Is possible.

  As mentioned above, although embodiment of this invention was explained in full detail, this invention is not limited by the specific description. For example, as the vibration system of the power generation apparatus, three or more mass members can be elastically connected in series via spring members, respectively, so that a multi-degree-of-freedom vibration system having three or more degrees of freedom can be obtained. According to this, high power generation efficiency can be obtained with respect to vibration input in a wider frequency range. When a multi-degree-of-freedom vibration system having three or more degrees of freedom is adopted, two mass members elastically connected to each other may be selected, and a power generation element may be provided only between the mass members. It is also possible to provide power generation elements between a plurality of sets of mass members that are arranged and elastically connected to each other.

  In addition, for example, two or more second mass members are elastically connected to the first mass member in parallel and via two or more second spring members that are independent of each other, thereby generating the power generation device. A multi-degree-of-freedom vibration system can be configured. According to this, since a plurality of second vibration systems are configured, the mechanical natural frequencies of the second vibration systems alone are made different from each other, and effective power generation with respect to vibration inputs in a wider frequency range is achieved. It is also possible to improve the power generation efficiency with respect to the vibration input in a specific frequency range by realizing it or by making the mechanical natural frequencies of the second vibration system alone the same.

  Moreover, as the power generation element, any power generation element such as a piezoelectric element, an electrostrictive element, or a magnetostrictive element can be adopted, and an electric power generation structure using an electret or an electromagnetic method using a time change of cross magnetic flux is adopted. You can also As understood from this, the specific structures of the second mass member and the second spring member constituting the second vibration system are not limited. For example, as the second spring member, A coil spring, a rubber elastic body, a bar spring, etc. can also be used. Similarly, the specific structures of the first mass member and the first spring member are not particularly limited. For example, a metal spring such as a coil spring, a leaf spring, or a bar spring may be used as the first spring member. .

  Further, in the power generation apparatus 10 of the above-described embodiment, the first vibration system 14 exerts a damping action on the vibration of the body 12 by adjusting the mass ratio of the first mass member 20 to the body 12. However, it is not essential in the present invention that the power generator has a function as a vibration damping device. In short, the mass of the first mass member may be smaller than 10% of the equivalent mass of the vibration member, and a vibration damping device such as a dynamic damper may be provided separately from the power generation device.

  Further, the vibration member is not particularly limited as long as the vibration input is sufficient for power generation. However, the power generation device according to the present invention is a vibration member in which vibrations of a plurality of types of vibrations are generated in different vibration frequency ranges. It is particularly preferably employed when the level is maximized. Specifically, for example, a washing machine whose vibration frequency changes depending on the amount of laundry, a refrigerator whose vibration frequency changes according to the operating state of the refrigerator, the vibration frequency according to running conditions, road surface unevenness, etc. In a car or the like in which the power changes, a casing, a body, or the like can be a vibration member for mounting the power generation device.

In the above-described embodiment, the mechanical natural frequency: _fr2 when the second vibration system 16 is handled as a one-degree-of-freedom vibration system is the same as that when the first vibration system 14 is handled as a one-degree-of-freedom vibration system. Mechanical natural frequency: It was set to a frequency lower than f _r1 (f _r2 <f _r1 ). At the same time, the mass of the second mass member 32: m ₂ is set so as to satisfy m ₁ * X> m ₂ * Q with respect to the mass of the first mass members 20, 54: m _1. (X and Q are resonance response magnifications of the first vibration system 14 and the second vibration system 16, respectively). However, the power generator according to the present invention is not limited to these embodiments.

That is, the mechanical natural frequency when the second vibration system 16 is handled as a one-degree-of-freedom vibration system: f _r2 is the mechanical natural frequency when the first vibration system 14 is handled as a one-degree-of-freedom vibration system. : even if than f _r1 is set to a higher frequency (f _r2> f _r1), the mass of the first mass member 20,54: m ₁ and resonant response magnification of the first vibration system 14: When the product of X is close to the product of the mass of the second mass member 32: m ₂ and the resonance response magnification of the second vibration system 16: Q (m ₁ * X≈m ₂ * Q), The amount of power generation can be increased by the interaction between the first vibration system 14 and the second vibration system 16. Therefore, in the power generation device according to the present invention, the mechanical natural frequency: _fr2 when the second vibration system 16 is handled as a one-degree-of-freedom vibration system, the first vibration system 14 is set as a one-degree-of-freedom vibration system. What is necessary is just to be different (f _r1 ≠ f _r2 ) from the mechanical natural frequency f _r1 when handling.

  Further, in the vibration power generation devices 50 and 52 shown in FIGS. 7 and 8, the lower mass 62 has a substantially bottomed cylindrical shape, and the upper mass 64 has a substantially flat plate shape. On the other hand, the accommodation space 56 is formed by covering the upper mass 64 from above, and the second vibration system 16 is accommodated in the accommodation space 56. However, the present invention is not limited to this mode. That is, for example, the lower mass may have a substantially flat plate shape, and the upper mass may have a substantially bottomed cylindrical shape in the opposite direction, or the first mass member may be a cylindrical member that opens laterally. A member that covers the side opening may be used.

10, 50, 52: power generation device, 12: body (vibrating member), 14: first vibrating system, 16: second vibrating system, 20, 54: first mass member, 22, 66: connected rubber elasticity Body (first spring member), 32: second mass member, 34: leaf spring (second spring member), 38: power generation element, 44: stopper means, 56: accommodation space

Claims (8)

In a power generation apparatus comprising a vibration system attached to a vibration member, wherein a power generation element attached to the vibration system converts vibration energy of the vibration member into electrical energy,
The vibration system includes a first vibration system in which a first mass member is elastically supported by a first spring member, and a second mass member elastically connected to the first mass member by a second spring member. A multi-degree-of-freedom vibration system configured to include the second vibration system,
The power generation element is disposed between the first mass member and the second mass member, and vibration exerted from the vibration member to the first mass member is transmitted to the second mass member. The first mass member and the second mass member are relatively displaced so that the vibration energy of the vibration member is input to the power generation element, and
While the natural frequency of the first vibration system and the natural frequency of the second vibration system are different,
The first spring member is formed of a rubber elastic body,
The rubber elastic body has a plurality of locations on the circumference of the first mass member between opposing surfaces in a direction substantially orthogonal to the vibration input direction in the first mass member and the attachment member attached to the vibration member. In addition,
The first mass member has a hollow structure with a void therein, and the second vibration system is accommodated in the void.
The second spring member in the second vibration system is formed of a leaf spring, and the power generation element is attached to the leaf spring, and the second mass member is attached to one end side of the leaf spring. On the other hand, the other end side of the leaf spring is attached to a support portion protruding from the first mass member into the space, so that the inside of the space is more inward than the peripheral wall portion of the first mass member. A power generator characterized by being positioned and supported by the power generator. 2. The power generation device according to claim 1, wherein the first mass member and the second mass member are set so as to be displaced in opposite phases in a vibration frequency range to be generated by the vibration member. The power generation device according to claim 1 or 2 , wherein the natural frequency of the second vibration system is set to a low frequency with respect to the natural frequency of the first vibration system. The power generator according to any one of claims 1 to 3 , wherein a natural frequency of the first vibration system is set to be higher than an electrical anti-resonance frequency of the second vibration system. The power generator according to any one of claims 1 to 4 , wherein a natural frequency of the first vibration system is not more than √2 times a natural frequency of the second vibration system. The resonance response magnification of the second vibration system is larger than the resonance response magnification of the first vibration system, and the product of the mass of the first mass member and the resonance response magnification of the first vibration system. but the power generation device according to any one of claim 1 to 5 which is larger than the product of the resonance response magnification of the mass and the second vibration system of the second mass member. The power generator according to any one of claims 1 to 6 , further comprising stopper means for limiting a relative displacement amount of the second mass member with respect to the first mass member. The power generation device according to any one of claims 1 to 7 , wherein the vibration member is attached to a portion where a plurality of types of vibrations having maximum vibration levels in different frequency ranges are exerted on the vibration system.

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